Applicant claims priority under 35 U.S.C. xc2xa7119 of International Application No. PCT/DE00/01516, filed on MAY 14, 2000. Applicant also claims priority under 35 U.S.C. xc2xa7120 of PCT/DE00/01516, filed on MAY 14, 2000. The international application under PCT article 21(2) was not published in English.
The present invention relates to a so-called gangway that is particularly suited for embarking on ships that have to dock on a floating pontoon such as used, for example in seaports, where the tidal currents cause noticeable differences in the level of the pontoon in relation to the wall of the jetty.
Such a gangway is known in the prior art from DE 198 20 780.8. The known gangway is comprised of two parallel sides, on which steps are arranged with a defined spacing from each other, and on which handrails are movably hinged on both sides on a railing, so that the handrails and the sides form a parallelogram with each inclination and the sides each are supported at the lower end on a roller and rotatably secured at the upper ends, whereby the trapezoidal steps are flexibly suspended with a spacing from the sites in which the sides are secured. It was found that said known gangway is afflicted with the drawback that the runners, which are secured on the undersides of the sides, have the same track width as the sides over the full length. This may cause damage to the stairway, which, under normal operating conditions, compensates listings of the pontoon of up to 12xc2x0 when listings of the pontoon in excess of 6xc2x0 occur at high tide.
Furthermore, the known gangways are normally comprised of two sides arranged parallel with each other. The sides are secured in an articulated manner at the upper end in the wall of the jetty and supported at the lower end by two rollers. Said rollers move back and forth on the pontoon depending on the level of the seawater.
It is perceived to be a drawback in connection with the known gangways that their adaptation to the conditions of the gradient of the individual steps of the gangway cannot be carried completely when changes occur in the level, for example between the edge of the seashore and a floating pontoon due to the tides, so that the entrance steps on the pontoon and the exit steps on land have varying conditions of their respective gradients. This poses a heightened risk of tripping, which may lead to accidents and claims on regression. Furthermore, it is perceived as disadvantageous that only one railing post is arranged on the sides of each step in order to avoid that neighboring steps and posts of the railing come into contact with each other at all angles of inclination occurring during high tide and when the inclination of the gangway reverses. The resulting distance between the posts of the railing is distinctly greater than the maximum spacing of 12 cm permissible on land. The public, which is used to uniformly spaced steps that comply with the regulations on land, therefore finds it difficult to adjust to step conditions that are varying within the confines of a gangway. Due to the relatively wide spacing between the posts of the railing, a risk is posed especially for children who can easily step through between such posts.
Therefore, the problem of the invention is to provide a gangway that is safely guided at high tide in order to mechanically protect the sides and the steps against destruction.
Said problem is solved according to the invention with the characterizing features of the independent claims.
Additional features essential to the invention are specified in the dependent claims.
The gangway as it relates to the invention is comprised of two parallel sides, in which trapezoidal steps are suspended in a hinged manner with a spacing (R=s=K) from a fixed point, and a handrail is suspended for each step parallel with the sides, and the steps comprise at least two stages of the railing whose line of alignment is arranged parallel with the sides of the trapezoidal steps, whereby the railing post located closest to the shorter side of the, trapezoid has a concave type of bulging, and runners are arranged on the undersides of the sides at a defined acute angle (xcex2) in relation to the longitudinal axes of the sides. Said runners are arranged in the lower area of the sides, and their mutual spacing (track width) (d) amounts to about half of the spacing (S) of the sides in the area serving as a support at high tide.
The sides are advantageously secured at the upper end of the wall of the jetty on a console, whereby the spacing K is effected by means of a bearing block. The lower ends of the sides are advantageously supported on rollers, which are rotatably supported in a U-shaped profile. In this way, and owing to the fact that the two sides are connected with each other in a fixed way, the stairway automatically exactly adapts to listings of the pontoon in the normal range of such listings.
The spacing (R) is formed on the steps in an advantageous manner by two tabs which are disposed at a right angle in relation to each other, whereby one of said tabs is connected with the step of the gangway in a fixed manner. The point of connection between the tab and the step is advantageously located with a defined spacing (E) from the longitudinal axis of the step, which takes into account unilateral out-of-center loads acting on the step, so that the step and its attached posts of the railing are jointly forming a stiff frame.
The individual steps are advantageously provided with a trapezoidal shape and a multitude of railing posts are arranged aligned in relation to the running direction in a way turned by a defined angle (xcex1), whereby the posts of the railing extend parallel with the slanted side of the trapezoid. In this way, the posts of neighboring steps are capable of being displaced by sliding in next to one another in the way of sliding blocks depending on the inclination of the stairway.
It is a special advantages that the railing post located closest to the shorter edge of the trapezoid comprises a concave bulging located in the lower area, the effect of it being that said post of the railing is not damaged by the longer edge of the trapezoid of the neighboring step when the inclination of the stairway reverses, on the one hand, and it is possible, on the other hand, to maintain the spacing of about 12 cm between the posts of the railing as required under the pertinent regulations.
The use of so-called self-aligning roller bearings represents another benefit. Said bearings are mounted on all steps and points of rotation of the handrail, so that no stiff connections of the sides of the stairway are created with the frames. This means that listings and inclinations of the pontoon are permitted to have some play within defined limits that are permissible under applicable regulations (up to 12xc2x0 in sports facilities). This has the advantageous effect that the support rollers located at the lower end of the sides will never lift from the deck of the pontoon and that no slanted entrance is formed on the gangway.
Owing to the rigid connection between the posts of the railing and the steps, on the one hand, and the flexibility of the points of fixation on the sides and handrails on the other, a parallelogram is described between the handrails and the sides of the gangway with each inclination.
It is especially very advantageous if the gangway as defined by the invention is provided on the underside of each side with a runner that is arranged at a defined acute angle (xcex2) in relation to the longitudinal side of the side, whereby the size of the angle (xcex2) is dependent upon the general engineering design of the gangway. The underside of the runner is tangential in relation to the support roller; the angle xcex2 represents the flattest inclination of the stairway on which a person is able to walk, and is limited downwards by the thickness of the material of the lowermost step plus a few millimeters safety spacing. What is prevented by this measure is that the mechanism of the rollers and the steps will not be damaged by any negative inclination of the gangway, i.e. at high tide.
At high tide, each runner is resting on its own roller on the narrow side of the pontoon. With respect to its effective length, which results from the local conditions, its track width has to be selected adequately narrow that the maximum listing the pontoon can assume will list the free end of the stairway by 12xc2x0 at the most.
The length of the runners arranged in the lower zone of the sides is advantageously a function of the respective side, or a function of the degrees of listing of the gangway most likely to occur.
The load-relieving effect of a space-keeping means (tie rod), which is mounted in the lower area of the runners, is advantageous for the overall stability of the gangway and the support of the steps.
The spacing of each individual runner or support surface r from the associated side is advantageously selected depending on the type of construction of the runners. The runners may advantageously be provided in the form of a solid profile having a cross section in the form of a xe2x80x9cTxe2x80x9d.
It is an advantage that the spacing of each individual runner from each individual side increases from the lower end of the runner in the direction of and up to the upper end of the runner.
The cross sectional shape of the runners can be selected in any desired way and is substantially dependent on the requirements the gangway has to satisfy with respect to its stability.